[Openexr-user] Reading from a stream (not a file)

[Brad Hards]

G'day,

I'm trying to update the KDE metadata plugin for EXR format files, and have 
run into a problem.

KDE4 has some fairly substantial changes in the way metadata gets managed, and 
one of those changes is that we no longer work on files, but only on a 
stream. The reason for this is so we can index into archives and so on.

However this is causing a problem with using OpenEXR, where the constructors 
appear to insist on having a filename. I tried to build a little adapter 
class, but I still needed a filename.

class ExrIStream : public Imf::IStream
{
public:
    ExrIStream (Strigi::InputStream *in):
        Imf::IStream (""), m_strigiStream(in) {}

  // other features omitted
}

but it throws:
terminate called after throwing an instance of 'Iex::ArgExc'
  what():  Cannot read image file "". Invalid pixel aspect ratio in image 
header.
Aborted

Any suggestions?

Brad

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